When you puncture a CO2 cylinder, does it get colder?

You do get something back from the delta-P in the pop bottle. Proabably not significant, but the extra-credit question is: what would happen if the bottling plant filled its bottles with very cold soda and you later opened the bottle at STP?

Don

 

There is indeed a direct relationship between pressure and temp

I always place beer in the freezer until its about -8 centigrade, obviously the alcohol prevents it freezing at this temp. BUT! If i go to -9 the beer stays liquid only as long as the cap is on the bottle. As soon as it is removed the beer begins to freeze and expand. This does not happen at -8

Beer i use is 5% alcohol

Not sure if letting pressure out will make it colder quicker, I suspect not but pressure certainly stops liquids freezing (and boiling) of course for longer than they would at atmospheric pressure.

Al.

 

Works similar for a Radiator Cap.....the pressure cap increases the boiling point of the fluid by about 3 degrees Farenheit for each pound of pressure.

 

Ok, so in the effort of resolving ambiguity... what's the answer? I think Al's post says that it may be better release the pressure. Does that mean it will cool faster under a vacuum?

 

Hoover or Electrolux? Canister or upright?

 

Hoover or Electrolux? Canister or upright?

Laughs!

Err, I dunno! give it a go and let us know. Get some of that tasty soda and get all them pesky bubbles out and put in freezer with an "un-debubbled" one. Test after 30 mins with a dip thermometer or probe.

You must of course begin with both test samples at the same stable temp.

Do let us know the results of your fizzy findings

:lol: Al.

 

I dunno the exact formulas or whatever but do know this. Temperature increases as pressure increases. However when it comes to those lovely cold gases that are cold in their little canisters, its because they are condensed down into their liquid form (REALLY REALLY COLD) and put into their canisters. The canister keeps the pressure of the gas/liquid the same, therefor preventing it from turning into 100% pure gas (it can't expand into a gas). So thefore since its still in liquid form, it is very cold. Take for example your common one, CO2. You find that everywhere from the CO2 cartridges in those pellet guns, to those keyboard dusters... to that soda in question also. It BOILS at -70 F. (boil, of course, meaning the phase in which liquid is turned into a gas). Therefore in order for it to be liquid in those canisters, that CO2 is sitting below -70F, and the only thing preventing it from going any higher is the fact that its under pressure and can't expand, therefore it can't boil and change from liquid to gas).

So, in short, just put the soda in the fridge when you get to work. It will probably take longer to cool, thats just because theres more to cool (you open, you release some CO2).

Besides... I'll take a warm carbonated soda over a cold flat soda

 

Seriously, everything's a heat engine. I'm too far away from my thermodynamics classes to decide if pressuring a gas and releasing it (It's irrelevant whether the gas is dissolved in a liquid at some point) is most like a Carnot, Otto, or Rankine cycle, but the rules of the game are than you get back the energy you put in, less entropy, and as far as entropy goes, you can't beat the efficiency of a Carnot cycle. The rest is details.

Don

 

Seriously, everything's a heat engine. I'm too far away from my thermodynamics classes to decide if pressuring a gas and releasing it (It's irrelevant whether the gas is dissolved in a liquid at some point) is most like a Carnot, Otto, or Rankine cycle, but the rules of the game are than you get back the energy you put in, less entropy, and as far as entropy goes, you can't beat the efficiency of a Carnot cycle. The rest is details.

Don

errrrrr, Yeah!
But if you put 2 x soda in the freezer will the one with bubbles cool faster,slower or at the same rate as the one without?

 

I say try it with a couple of beer...much more fun

They won't stay in the freezer long enough to do a complete experiment but after a couple you won't care. They will both taste good :lol:

 

>>But if you put 2 x soda in the freezer will the one with bubbles cool faster,slower or at the same rate as the one without?

If the masses are the same and there's no phase change, the same. The phlogiston starts one place, winds up someplace else, and travels the same path.

Why do we Americans chill beer to the point where we can't taste it?

(Besides the fact that we don't have any Lucas-built refrigerators.)

Don

 

I know that I learned when I was in the Service that a CO2 fire extingisher would cool a sixpack of beer in about 3 seconds.

 

I know that I learned when I was in the Service that a CO2 fire extingisher would cool a sixpack of beer in about 3 seconds.

Now there is a fact I did not know...The forum is a valuable source of information...Thanks 8)

 

Place 6 pack in small trash can and shoot the C02 extingusher in. Dont do it with Halon, $25 a pound.

And those key board "Dust Off" cans, dont turn one upside down and spray your fingers, unless you want frostbite. They are filled with 134a refrigent and when it expands, its cold. All the old ones were filled with R-12 up untill it was banded. It will kill hornets/yellowjackets before they can leave the nest. I have also used it to cool my starter down when stuck with a no crank when hot. DaveJ

 

Why do we Americans chill beer to the point where we can't taste it?
Don

I can't believe this question needs to be seriously asked. :lol:

 

There is indeed a direct relationship between pressure and temp

I always place beer in the freezer until its about -8 centigrade, obviously the alcohol prevents it freezing at this temp. BUT! If i go to -9 the beer stays liquid only as long as the cap is on the bottle. As soon as it is removed the beer begins to freeze and expand. This does not happen at -8

Beer I use is 5% alcohol
Al.

Stangely enough I saw the proof of this tonight. Caught up with a friend of mine on another motorcycle forum. He pulled two bers out of the freezer - opened them. took a swig out of his and then turned it upside down, not a drop came out.....

... and yes, Aussie beer is around 5% alcohol.

 

the mythbusters worked on this king of problem but it was about beer.

ice and water is the best cheapest/fastest method.

but for a real rush a CO extinguished will do the job in a second or two.

 

Heat conducts through solids and liquids faster than through gases. The CO2 bubbles would be insulators.

Two bottles of carbonated drink in a freezer. One unopened and the other briefly opened and resealed, but with no liquid removed. The opened bottle will allow CO2 bubbles to form due to the drop in pressure inside the bottle.

An unopened bottle with no bubbles would have more surface area of it's liquid exposed to the cold air of the freezer. The bubbles that nucleate on the sides of an opened bottle would reduce the surface area from which heat could radiate.

This would also be the case for heat conducted from the bottle while lying on it's side in the freezer or submerged in a cooling bath. The CO2 bubbles reduce the area from which heat can escape.

The more heat the bottle can give off at one time, the faster it will cool.

Answer: Cool your bottles either unopened, or flat. Either way, no bubbles.

Answer Plus: Cool them in an ice and water bath for quickest results without wasting a CO2 fire extinguisher.

Answer Plus Plus: The drop in pressure when opening a carbonated drink will cause a slight drop in the temperature of the contents, but a significant change in the temperature of the air in the bottle. Ever notice the little cloud when you open a bottle or can of carbonated drink? That's the water in the in the air quickly condensing due to the pressure drop.

 

I didn't see this question soon enough. I'm a chemist, so have dealt with this equation. The ideal gas law is for a gas at one state, not for a change of state. It does show the relationship between different properties though. However, you are dealing more with a liquid than a gas, which does not really change volume. While the can may have increased in pressure when bottled, the energy in the drink (in the form of heat) has had time to equilibrate with the surrounding environment. I don't believe higher pressure makes it slower to cool a canister, but rather the pressure will change as you cool it. A good example is to take a blown up balloon and place it in liquid nitrogen. The balloon will collapse flat, but left out you can watch it expand back to it's original shape (pretty neat to watch). What you are using here is more Gay-Lussac's law (http://en.wikipedia.org/wiki/Gay-Lussac's_Law) which shows that pressure and temperature are proportional to each other (if one goes up, the other goes up) assuming volume is constant. With the exception of the bubble formation on the sides mentioned by another user, there should be no difference in the relative cooling between an open can and a closed can if they start at the same temperature. Plus, you will get a slight drop in temperature when you open the can, so all the more reason to keep it closed.

As for cooling in a hurry, the ice bath works great (water can accept a large amount of heat), but adding salt will help to lower the temperature even more, just like making icecream. Otherwise, you could take some small diameter copper tubing (glass would be great if you can find it) and make a coil with space between each coil. Place this in a water tight box that you can fill with ice water. Pour your soda in the top and allow it to run through the coil and into a glass. It'll cool in seconds and would be neat to see. Or, take the easy way and just add ice cubes to a glass and pour your soda in. Not nearly as spectacular, but it works.

David

 

Or, take the easy way and just add ice cubes to a glass and pour your soda in. Not nearly as spectacular, but it works.

David

+1

It can be spectacular as the ice fractures itself as its melting. And you can make a game out of it by trying to pour it without having it foam over the sides :lol: